The invention relates to a safety device designed in particular, but not exclusively, for food cutting apparatus.
Food cutting apparatus known in the field, such as vegetable cutters or meat/vegetable cutter units, have among other things, a motor unit enabling control and motorization of a cutting tool and a device, commonly called a vegetable cutter head, for feeding and cutting the food products. The vegetable cutter head may have a bowl that is removable or integrated with the motor unit, of a suitable shape. The apparatus may or may not be arranged for continuous discharge of the treated products (closed bowl or open bowl). Typically, a cutting disk or tool is located inside the bowl and is moved by the motor to make the desired cuts (slicing, grating, etc.). The bowl has a cover, and may have a discharging disk.
The cover enables introduction of food products to be processed. Food products are fed through the cover by guiding them through one or a plurality of vertical tubes or chutes. The cover also protects the user by preventing ejection of the processed product outside the bowl and, above all, by precluding the user from being cut by touching the moving disk.
Introduction of food products into the machine is accomplished by positioning them in a suitable chute and by pushing them against the disk with the help of a pusher. Removing the pusher leaves the disk exposed at the lower end of the chute. For chutes large enough to admit an appendage of the user, it is advisable, if it is desired to protect the user from risk of injury, to permit operation of the motor only when a physical element is present to block the chute inlet.
It is known by FR-A-2 147 361 (VERDUN) to provide a mechanical safety device responsive to the presence of the cover on the bowl, this safety being obtained by means of a sliding rod arranged along a line with the bowl. The lower part of the rod comes to bear when the cover is positioned against a switch included in the base, and operated by action of a cam carried by the cover. This sort of device does not provide suitable chute safety and Instead, safety is addressed by providing chutes that have a long length and/or a limited cross-section to prevent user contact with the cutting disk.
A device for magnetically accomplishing this control function between the pusher and the motor drive is known by U.S. Pat. No. 4,821,968 and uses a set of magnets and reed (flexible blade) switches, or switches of the Hall effect type. This device relies on an electrical response; and, moreover, control using a magnetic field is perhaps more delicate than desired for considerations of safety.
Mechanical devices are already known which consist in operating a power circuit breaker only when the chute pusher is in a safe position. Such a device is described in U.S. Pat. No. 4,674,690 in which the chute is surrounded by a sleeve provided with means for activating the power circuit breaker, in which the pusher is enclosed.
The present invention seeks to cope with all these problems in a control between a pusher, which pushes the products inserted in the chute, and the drive of the motor. This mechanical solution permits safe use of a chute having a large cross section (e.g., as big as a person""s hand).
According to the invention, a safety device is provided for a food processor with a rotating tool, an electrical motor unit on which is mounted a bowl that is closed by a cover, a motor shaft passing through the bottom of the bowl, and wherein the device can receive various tools. The cover defines a chute, and carries a safety rod arranged along a line with the bowl and operating a switch arranged in the power circuit of the motor unit. According to an inventive aspect, the pusher is guided for translation in a pusher-guide. The pusher-guide is articulated at the top of the chute and is mechanically connected to push against the top of the safety rod, such that a small pivoting of the pusher-guide from its lowered position causes stoppage of the motor.
The invention provides a mechanical safety device for a food processor of a type that may require action by the user to advance food products for cutting. The device is associated with a motor unit on which an optionally-removable bowl is arranged and is closed by a cover, the cover likewise optionally being removable from the bowl. The device controls the motor based on the position of one or more movable parts, for preventing access to an area of potential injury to the user, while the motor is on. In one embodiment, a pivoting movable part is formed by a pusher-guide, that may or may not be free to pivot while a pusher is sliding in the pusher-guide. The upper portion of the chute is safely obstructed when the motor is on, either by means of the pusher itself, or by the pusher-guide. The pusher generally has a reduced cross section, and at a lower end carries a plate having a cross section which is substantially equal to that of the chute. The pusher handle freely slides in the pusher-guide. The plate at the end of the pusher can be extracted from the chute only when the plate is lifted out of the chute by pulling on the handle.
Pivoting of the pusher-guide causes translation of a connecting rod, the lower end of which bears against the upper part of a safety control rod of the bowl. Pivoting of the pusher guide can be accomplished only when the pusher plate is retracted into abutment against the pusher-guide.
The result is a control of the drive of the motor based on the position of a movable part that obstructs manual access to the area of cutting risk, safely permitting use of a chute defining an aperture with a large cross section.
According to another feature of the invention, the pusher-guide drives a connecting rod by means of a first articulation. By means of an articulation at its second end, the connecting rod forces rotation of a crankshaft around a second pin that is fixed with respect to the cover. The crankshaft in turn drives a first rod, by means of its first articulation which is common with said connecting rod. This first rod acts on a switch located in the motor housing unit through the second rod, guided for translation in a line along the wall of the bowl. The second rod is returned upwardly by a spring.
A mechanical device as described is economical and can directly act on an electric switch that couples or decouples currents compatible with the motor. Therefore, the apparatus is very simple and reliable and its manufacturing cost is more moderate than that of other safety devices.
The pusher is connected to the cover of the vegetable cutter by means of an intermediate part called the pusher-guide. The pusher-guide pivots around a horizontal pin which is positioned at the upper part of the chute and permits translation of the pusher. If the pusher is in the chute, food products are introduced by first drawing the pusher up to the upper level of the chute, and then pivoting the pusher-guide free of the inlet of the chute. When the chute is filled with food products to be processed, downward pressure is exerted on the products after causing the pusher-guide to pivot back so that the pusher is over the top of the chute, and then causing the pusher to vertically descend in the chute. Closing the guide and lowering the pusher pushes the product against a tool such as a cutting disk. The process is repeated by raising and removing the pusher, refilling the chute, etc.
Controlling motor operation based on the position of the pusher-guide ensures that the motor does not operate unless the pusher is obstructing the inlet of the chute. An assembly of rods, arranged between the cover and the pusher-guide, controls a safety switch which is placed near the motor. The translation movement produced by the pusher guide is transmitted by the safety rod in the bowl to activate the switch . A return spring can returns the rod to an upper position when the pusher-guide is not in the working position.
According to the inventive kinematics described herein, two joint problems of with this type of system are solved:
When the pusher-guide is closed, the system advantageously exerts a resisting force to opening, which is enough to permit raising of the pusher without driving open the pusher-guide until the pusher is completely raised. Otherwise, rocking of the pusher-guide before the pusher is fully retracted will produce rubbing of the pusher against the sides of the chute. Such rubbing at least is detrimental to ergonomics, and may lead to complete blocking of the mechanism by buttressing. At the same time, the resistance force against opening must not be too high since it would then be a constraint for the user.
The system should stop the motor even when the pusher-guide is not rocked very much, i.e., well before it becomes possible for the user""s hand to obtain access to the tool. It is therefore advantageous for the mechanism to produce a relatively robust stroke of the rod contained in the cover, responsive to a small angular displacement in the direction of clearance of the pusher-guide.
A small upward pivoting of the pusher-guide of the chute from its lowermost position causes the motor to stop. When preparing to lower the pusher into the chute, it is possible to enable operation of the motor while permitting the products being processed initially to protrude slightly above the upper end of the protected chute.